There is a difference between the mass and weight of a body because

The difference between the mass and weight of a body lies in their fundamental definitions. Mass refers to the amount of matter in an object and remains constant regardless of location or gravitational field strength. Weight, however, is the force exerted on an object due to gravity and varies depending on the gravitational field strength. Therefore, mass remains constant, while weight changes with location. This distinction is crucial in physics as it affects how objects behave under different conditions. Option [B] Mass remains constant, while weight is variable accurately describes this difference, aligning with the fundamental principles of physics. Hence, option [C] Both are true is incorrect, as mass is not variable, and weight is not constant. Similarly, option [D] Both are false is also inaccurate, as the statements in option [B] are indeed true.